The present invention relates to a packaging material, preferably in tube form, suitable for the manufacture of casings for pasty goods, preferably for the manufacture of artificial sausage casings, and to a process for preparing such material. More especially, the invention relates to the production of tubular sausage casings having a base layer principally of regenerated cellulose and a surface layer, preferably on the inside of the casing, which is comprised of a vinylidene chloride-containing copolymer and is substantially impermeable to water vapor, oxygen, and flavoring substances. Furthermore, the invention pertains to tubular casings for pasty goods, especially synthetic casings for use in the manufacture of sausages produced from the packaging material. The artificial sausage casings according to the invention are particularly suitable for sausages which are treated with hot water during their manufacture.
Tubular casings according to the invention are particularly well suited for the manufacture of shirred artificial sausage casings which are used in the sausage manufacturing industry and as synthetic sausage casings.
Tubular casings which are commercially utilized as synthetic sausage casings are those based upon cellulose hydrate and these tubes generally have either on their inside or their outside surface a coating layer of vinylidene chloride-containing copolymer. These tubes are available either as rolls or as individual units one end of which is already closed. Tubes which are suitable for use as synthetic sausage casings and which do not carry any barrier layer coating on their surfaces have for many years been gathered up or shirred by means of suitable machines well known for this purpose. The procedure is carried out by pleating the tubes in the longitudinal direction into hollow rod-shaped structures. These structures shall be referred to hereinafter as shirred casings. The procedure for producing the shirred casings is known under the designations "shirring" or "gathering".
These shirred casings are then filled with a sausage mixture by means of sausage filling machines of known type, the sausage filling recipe being stuffed into the shirred casing closed at one end, so that the shirred casing is continuously unfolded and extended.